Magnetic pick-up device



Nov. 10, 1931. S. MCCLATCHIE 1,830,801

MAGNETIC PICK-UP DEVICE Filed Dec. 7, 1929 2 Sheets-Sheet 1 ,HVEHTOE' BY6tanleg me C'IaZc/vie HTTORNEYT Nov. 10, 1931. s. MCCLATCHIE MAGNETICPICK-UP DEVICE Filed Dec. 7, 1929 2 Sheets-Sheet 2 IHVEIYTO/i SfanIeq meClafchie HTTORHEY Patented Nov. 10, 1931 UNITED STATES PATENT OFFICESTANLEY MCCLATCHIE, or neanin-wrmvmnsnonr,GERMANY MAGNETIC lICK-UPDEVICE v 1 Application flled December 7, 1929, Serial No. 412,490, andin Germany July 5, 1929.

This invention relates to magnetic pick-up devices, especially for usefor reproducing sound from phonograph records. 7

Phonograph pick-ups as hitherto known, have the drawback that it isdifficult to assemble, interchange and adjust individual parts. This isparticularly objectionable in the case of the esential moving part ofthe pick-up, the armature with its associated damping means of rubber.As is well known, rubber rapidly loses its original elasticity, so thatin the course of from four months to one year, the operation ofthepick-up is markedly impaired.

It is the object of this invention to overcome the afore-mentioneddrawbacks and to provide -a sound-box which consists essen tially of twoparts, 1) a casing with themagnet, spool and pole-pieces, and (2) areadily detachable and adjustable supporting member for the armaturewith its rubber damping in providing simple clamping means for keep ingthe needle in its supporting element,

which clamping means are arranged so as not to oscillate with theneedle.

Further objects of the invention will b'ecome apparent fromthe followingdescription taken in reference to the appended draw ings and disclosing,by way of illustration,

some practical forms of embodiment of the invention. 7

Referring to the drawings, Figure 1 shows 'a preferred form of pick-upin accordance I with my invention, in a longitudinal section.

Figure 2 is a cross-section taken at right angles tothe section ofFigure 1.

Figure 3 is an enlarged cross-section of a idftail of Figure 2, taken atthe section-line -B. Figure 1 illustrates an alternative construction.

fastening of the spool flange to the separating i Figure 5 is afragmentary section of a de-, vice as shown 1n Figure 4, but withmodified means for holding the needle in an operating wall between themain casing and its detachable part, by means of eyelets, which,'at thesame time, serve as terminal connections for the coil. j v I Figures 8and 9-show respectively, sections taken on' the section-lines A-'B and'C-'D of Figure 4. r 1 Similar reference numbersreferto similar elementsthroughout, the different views of the drawings. 7. y j c Referring toFigures land 2, a magnet 1, which is preferably a permanent magnet andwhich may be rotated by means, of a knob 26, is mounted attheupper partof-a .0255 ing 2, and 2a, with a resilient spacing Inem-j ber placedbetween. The spool 4 has flange 5, whichis clamped, together with thepole-pieces :6 and tl1Qd1SC37, between the two;

halves of the ,casing2'and 2a. The casing bushings 10, 11. The disc,7.serves to pre-' A- further object of my 1nvent1on conslsts surrounded bya rubbercushion13,which is held by air inward tubular extension 1 of thesupporting member 15. The upper" part of the armature tube. 12 ,isprovided with I indentations 16, which serve as a stop for. the needle,which thus can only be. inserted to a predetermined depth. The needle 17is held in operating position in the armature .12 by means of a clamp18, which, through the spring 19, exerts a pressure against the needleat the point which is theaxis of oscillation. At'this point, the clampdoes not inter ferewiththe needles movement. The clamp hasa'press-button portion 20 and atongue 21, which latter serves to. forcethe needle into the wedge-shaped-polition 12a of the armature 12.. (SeeFigure 3.) Infthe embodiment shown in Figures 4 and 7 the clamp consistsof a bent elastic wire 21a, carried by the member; 15 and havinganoutside extension through a slotof the casing. In this embodiment, thearmature holder 15 is extended to form the cup-shaped lower casingportion, whichin Figure 1 is, the separate'part 2a. The spoolflange 8 ishere secured to the casing 2 by the eyelets 22, shown on an enlargedscale in Figure 7.

In the embodiment, according to Figures 5 and 6, the pressure member forthe needle 17 consists of a tongue 26 of a slider 18a, which is forcedagainst the needle 17 through the action of a rubber cushion 23. Vhen itis desired to exchange needles, it is merely necessary to de'presstheportion 20 of the slider 18a.

The detachable part 15 with associated armature system, is secured tothe main casing by means of the set-screws 24 and 25. A resilient gasket28 is interposed. The washer 27 of Figure 1 servesto strengthen theholder 15 where the screws force the holder against the gasket. l

The various forms just described have, in common, that the armaturesystem, with an associated supporting structure,is detachably andadjustably secured to the main body of the pick-up. Provision is thusmade for readily renewing the armature system as soon as the rubberdamping begins to deteriorate.

In practice,the dealer selling the device would carry in stock fresharmature systems for renewal. He has merely to remove the two setscrews24 and 25 and attach a new system. The positi on of the armature betweenthe pole pieces is readily adjusted by means of a phonograph needleinserted in one of the transverse holes shown in the screw Thisadj-ustment ma y be carried out 'while the picle up is'actu'allyplaying-,which makes the operation simple even for a layman, as he maythus gauge the correct adjustment by ear.

Furthermore, the interchange of needles is greatly'facilitated by theuse of a clamp, instead of a set-screw, as has heretofore beencustomary. This construction has the further advantage of relieving thearmature of the undesirable additional weight of the setscrew with itsassociated threaded holder.

It is evident that my invention may be embodied in other forms and inother associations of elements than thosehere shown, and that the scopeof the invention is not to be construed as limited to the particularstructures and combinations described and illustrated.

What I claim is':

1. A sound reproducing pick-up device for phonographs and the like,comprising, in combination, a main supporting structure, a

detachable part of said structure, a phonograph needle to be subjectedto mechanical oscillations corresponding to the oscillations of sound tobe reproduced-ii cushion of'elastic material carried by said detachablepart to simultaneously serve for "holding said needle in operatingposition and acting as a dampening means for said mechanical oscil-'lations.

In a sound reproducing pick-up device, tor phonographs and'the like,comprising, in

combination, a main casing structure, a detachable part of said casing,an element subjected to mechanical vibrations corresponding to thevibrations of sound to be reproduced and a cushion member of elasticmaterial carried by said detachable part to serve as a support of saidelement and as a dampening means of said mechanical vibrations.

'3. In a sound reproducing pick-up device for phonographs and the like,comprising, in combination, a main casingstructnre, an operating magnet,a detachable part of said casing, .a phonograph needle subjected tomechanical oscillations corresponding to oscillations of sound to bereproduced, a cushion member of elastic material carried by saiddetachable part, a magnetic armature cooperating with said magnet heldby said cushion member and engaging said needle in a clamping position,whereby said cushion, simultaneously serves as a pivotal support of saidneedle and as a dampening-means of said mechanical oscillations.

4. Ina sound reproducing pick-up device for p'honographs and the like,comprising. in

combination. a main casing, a detachable part of said casing. a magnetstructure carried by said casing, a cushion member of elastic materialcarried by said detachable part. a

phonograph needle to be subjected to mechanical oscillationscorresponding to the oscillations of soundto be reproduced, a ma gneticarmature cooperating with said magnet, being held in a clamped positionwithin said cushion member. and engaging said needle, said cushionserving as a support for said armature and as a means for dampening itsoscillations. p

In an electro-magnetie sound re- 'n-oducing'pic'k-up device forphonographs and the like, comprising, in combination, a main casingstructure, a magnet carried b v said structure, pole pieces of saidmagnet. a detachable part of said main structure, a phonograph needle tobe subjected to mechanical oscillations corresponding to theoscillations of sound to be reproduced, a cushion of elastic materialcarried by said detachable part and arranged between said pole pieces,said needle being supported by said cushion. serving at the same time asa dampening member for said mechanical oscillations.

6. In an electro-magnetic sound 'reproduc ing pick-up device forphonographs and the like, comprising, in combination, a main casingstructure,a magnet carried by said struc V material carried by saiddetachable part and" arranged between said pole pieces, a sleeve-- likemagnetic armature held in a clamped position Within sa d cushion andengaging to be subjected to mechanical oscillations corresponding to theoscillations of sound to be reproduced, a metallic sleeve within saidrubber tube to serve as operating armature of said pickup device andholding said needle in operating position, said rubber tubesimultaneously serving as a dampening member of said mechanicaloscillations 8. In a phonograph sound reproducing pick-up device, asdescribed in claim 7, wherein said detachable part is adjustably con-'nected to said main structure by means of intermediate layers ofelasticmaterial.

9. In an electro-magnetic sound reproducing pick-up deviceforphonographs and the like, comprising, in combination, a main casingstructure, a magnet within said casing, a detachable part of saidstructure, pole pieces of said magnet, a rubber tube element carried bya tubular extension of said detachable part and arranged between saidpole pieces,

a metallic sleeve within said rubber tube to serve as operating armatureof said pick-up device, a phonograph needle to be subjected tomechanical oscillations corresponding to the oscillations of sound to bereproduced, said needle being carried by said sleeve in clampedposition, whereby said rubber tube simultaneously serves to support saidneedle in operating position and to dampen said mechanical oscillations.I

10. In a phonograph pick-up device, as described in claim 9', wherein.said detachable part is adjustably connected to said main casingstructure by means of lntermediate elastic layers.

11. In an electro-magnetic sound reproduc- 7 by a tubular extension ofsaid detachable needle in said armature sleeve, said pressure elementbeing arranged to be movably mounted to apply its pressure to saidneedle and to hold it in its armature.

12. In an electro-ma etic phonograph pickup device, as descri ed inclaim 11, in which. said pressure element consists of a sliderassociated with said main casing provided with a slot for receivingneedle armature and a spring member between said slider and said maincasing pressing said needle against the inside of its armature.

13. In an electro-magnetic sound reproducing pick-up device forphonographs andthe like, comprising, in combination, a main cas-' ingstructure, a magnet within said casing, a detachable cup-shaped part ofsaid structure, pole pieces of said magnet arranged within saiddetachable part, a rubber tube element carried by an inward tubularextension of said detachable part and arranged between said pole pieces,a metallic sleeve within said rubber tube to serve as operating armatureof said pick-up device, a phonograph needle to be subjected tomechanical oscillations corresponding to the oscillations of sound to bereproduced, said needle being carried by said sleeve in operatingposition, whereby said rubber tube simultaneously serves as a pivotalsupport for said needle and as a dampen ing member of said mechanicaloscillations and a pressure element, together with a spring for holdingsaid needle in said armature sleeve, said pressure element beingarranged to be inovablyi mounted against the action of said spring onsaid detachable part to apply its pressure to said needleand to hold itin its armature. i g

14. In an electro-magnetic phonograph pick-up device, as described inclaim 13, in which said pressure element consists of a metal plate witha bent over part and an elastic member co-operating with said bent overpart to exercise pressure of said needle to retain it in its positionwithin said armature. In testimony whereof I affix my signature.

STANLEY MCCLATCHIE.

